Debris including litter, dust, sand, gravel and abrasive used during winter time and the like are often found on roads, parking lots, airport runways and other surfaces aimed at circulation of vehicles. Since debris may damage vehicles circulating on such surfaces and/or impair the security of the passengers thereof, removal of sand, gravel and the like from road surfaces has become very common.
Amongst the most common technologies developed for removing debris from road surfaces are the self-propelled sweeper vehicles. Typically, such vehicles are provided with a rotary brush for lifting the debris toward a container, where the debris are captured. A conveyor such as a vacuum conveyor or a belt conveyor then carries the debris from the container, toward a recipient or reservoir mounted in the vehicle, where the debris are stored. Once the reservoir has been substantially filled with the debris, the vehicle travels to a landfill or depot, where the reservoir is emptied.
The quality of cleaning of these types of systems tend to be satisfactorily in that minimal amounts of debris are found on such surface after the passage of the vehicle. However, the efficiency of these systems is greatly reduced by the limited size of the debris reservoir, involving frequent interruption of sweeping activities for the vehicle to travel back and forth to the landfill areas. In some cases, the travel time may represent up to 75% of the operation time of the vehicle while cleaning operation per se only represents 25%. As such, traditional sweepers tend not to be cost effective.
To minimize travel time of the sweeping vehicles, other vehicles such as dump truck may be brought to the cleaning sites. In these occasions, the debris reservoir of the sweeping vehicle is emptied into the dump truck, which will further deliver the debris to the landfill. Although this mode of operation considerably reduces travel time, interruption of the cleaning activities is still required and efficiency of the sweeping vehicles still not optimized.
To avoid the need for emptying debris reservoirs, some have proposed mechanical sweepers provided with conveyor assemblies for carrying the debris from the road directly towards another vehicle. For instance, some have come with a mechanical sweeper towed by a vehicle such as a dump truck. Such a mechanical sweeper comprises a pickup broom transferring debris on a first conveyor belt, which in turn transfers the material on a second conveyor belt. The second conveyor belt conveys the material into the dump body of the dump truck. Because the sweeper is towed by a vehicle, it must be detached from the vehicle when the latter is full or, alternatively, be brought to disposal site. In any event, operating or cleaning time tends to be reduced by any of these additional operations.
Some others have come with self-propelled mechanical sweepers. Such mechanical sweepers of the prior art comprise a pickup broom transferring debris toward an auger (i.e. an endless screw), which directs the debris on a first belt. A second belt conveyor carries the debris from the first conveyor toward an auxiliary vehicle. Larger debris found on roads (i.e. rocks, plastic bottles, wheel covers) tend to remain jammed in the auger and impair proper functioning of the sweeper. Further, the mechanical sweepers of the art need to be transported from one cleaning site to another on a truck or a trailer as they tend to be very slow.
Therefore, it would be desirable to be provided with a mechanical sweeper capable of independently and efficiently traveling between cleaning sites and capable of handling relatively large debris.